Monoazo dyestuffs



MONOAZO DYESTUFFS Achilles Conzetti, Basel,;Switzerland, assiguor to J. R.

Geigy A. G., Basel, Switzerland, a Swiss firm No Drawing. Application February 5, 1953, Serial No. 335,405

Claims priority, application Switzerland FebruaryS, 1952 7 Claims. (Ql.260.-200) l The present invention concerns the production of monoazo dyestuffs which are suitable for the dyeing of natural protein fibres and of synthetic polyamide fibres. When dyed from a neutral to. weakly acid bath, they produce very even and fast to wet dyeings, particularly on wool 'lthas been found that valuable monoazio 'dyestufls are obtained if diazotised 1-amino-8hydroxynaphthalene- Unit Stems Patent ice j Patented June 21," 1955 the presentinvention produced as described above corre-' sponds to the following formula; v .3

wherein :Y representshydrogenor themethyl group and 1 Z represents hydrogen a low molecular alkyl or alkoxy 3.6-disulphonic acids or their'O-acyl derivatives are -coupled with dibenzylaminobenzene compounds coupling in the p-position to the amino group and if necessary, 7

saponifying the acyloxy group to the hydroxyl group. In this way, monoazo dyestuffs are obtained of the general formula: Y

wherein A represents an unsubstituted ,orsubstituted pphenylene radical and B represents a similar benzene radical.

Diazotised 1- amino-8-hydroxynaphthalene-3 .o-disul phonic acids can be used in the process according to this invention as diazo components. More advantageous however, are their O-acyl derivatives, particularly the 1-.

The 'dyestufis fare'tformed advantageously in amedium "which is weakly. acid to Congored,.preferably in, =or.

inthe presence ofiorganic solubility promoters .because'f of:the'difl'icult "solubility of the couplingcomponents Ass uch, the'lower alcohols, ketones,andfattyacids'and, if'necjessary also pyridine bases whichcanbe mixed with-- water may be employed;

The 'saponification of the acyloxy ifprese'nt, to the'hy'droxyl' group can be done, for example, inaqueous: solutionwithdiluted caustic alkalies at araisedtemper ature or; in 70-90% sulphuric acid atfroom temperature; in the second case, the dyestuffs are afterwards converted into theialkali-salts. i T

In the form of their alkali"salts,;th e"dyestuffs accord- 1 ing to this inventionarered.tojbrownpowders which amino-8-benzene sulphonyloxy and 1-amino-8-tos yloxy-- 3.6-disulphonic acid because their diazo compounds couple better. p i

As coupling components in the process according to the present invention canbe used all reactive dibenzyl anilines, i. e. those with a free p-position to the amino group. It is advantageous to use suchncoupling components, the coupling activity of which is not reduced by electron-attracting substituents in they rings A and B. As well as unsubstituted dibenzylaniline, also the dibenZylaniline derivatives capable of coupling containing substituents such for example as low molecular alkyl, alkoxy and acylamino or phenoxy groups, may'beemployed. These substituents can be either in the ortho, or more advantageously, in the meta-positionto the amino group in the benzene ring A, or they can'occupy the 2.5;positions.

The 3-.alkoxy-l-dibenzylaminobenzene compounds, e; g. f

3-methoity and the 3.6-dimethoxy-l-dibenzylaminobenzene are particularly easy coupling .azo components which couple even with the non-acylateddiazo compoundsac cording to the present invention. Particularly pureand fast to light dyestuflfs according to this invention are obtained however, if the benzene ring A is unsubstituted or if it is methyl substituted in the 2-, 3- or 2.5-positions. Substitution in the benzyl radicals has only a slight influence on the shade; apart from unsubstituted benzene rings which are advantageous, those substituted inthe oand p-position to the methylene linkage by groups such as alkyl and alkoxy groups may be employed.'

' dissolve in water with'ayellowish red to blue-red colour.

' They are characterised by good drawing powerjonto .wool

from a weakly acid bathand they producejvery level; 1 pure, wool dyeings which, have very good tastness 'to' .7 milling andsea water; Their property of dyeing" the roots I land tips of theiwool verylevenly should beparticularlynoted". In many cases thedyestutfs according tothe' pres} 7 Q ent. invention are very fast' to light.

The following examples illustrated the invention, withiout limiting it in any way. Where not: otherwise stated,; parts t a're. given as parts bywa m and ,the temperatures are givenin degrees centig'rade. Therelationship'of'parts by;weight to parts by volume'is as that of ikilogramrnes I to 1 litres. v;

Example l f nol. Themixture is 'keptwith a wealrlyacidreaction to Congo :red by the dropwise addition of. sodium acetate solution After stirring. for some 7 hours at 18-30 f the dyestufi formationis complete:- 3 The alcohol is distilled off, the -residue is neutralised-with sodium carbonateahd thenlcaustic sodaupto, aiconcentration of- 4%g1is raddedw After stirringlfor 31 hour at 80-85 .thes'aponification of 'the-. tosyloxy :to the fhydroxyl group is-completeQ; The solution is neutralised with hydrochloric acid, the'formed dyestufl isfsalted out and after cooling, liltered ofl and dried.

"Thef dyestuif, a light red powder, dissolves'idwater V with a red colour and produces purered dyeings; on wool w from a weakly acid bath. g The 'dyeings have very good;

' wetffastneiss properties and 'very good fastness tolightj;

A particularly valuable group of dyestuffs according to zene, 30;l parts of di'-(4'-'methylbenzyl)-aminobenzene or 333' parts of di '-(4"+methoxybenz'yl) -aminobenz'e'ne are used.

f1A 'dy estufi with very similar properties is obtained V, in he'jabove example instead of'jthe dibenzylaminobem Example 2 31.9 parts of the sodium salt of 1-amino-8-hydroxynaphthalene-3,6-disulphonic acid are dissolved in 400 par fho a e he. olut on. o e and Pa t of concentrated hydrochloric acid are quickly added at 30. The solution is di-azotised at O2 with a solution of 6.9 parts of sodium nitrite in parts of water whereupon the whole is stirred for 2 hours at 072. The yellow suspension of the d-iazo compound is added at -32 to a warm solut-ion of 33 parts of ZQS-dimethoxy-l-dibenzylaminobenzene in 600 parts of ethanol which has been prepared hot and the whole is stirred at this temperature. The reaction is kept weakly acid to Congo red by the dropwise addition of an aqueous sodium acetate solutiori until after 16 hours the diazo compound has disappeared. The suspension is heated, the alcohol is distilled ofi, the residue is neutralised with sodium carbonate and the dyestulf is salted out After cooling, the dyest-uif is drawn oif under suction and dried. It is a brownred powder which dissolves in water with a bluish-red colour. It dyes wool from a neutral to weakly acid bath in very level blue-red shades. The wool dyeings have very good wet fastness properties and fairly good fastness to light.

The same dyestuli is obtained if instead of 1-amino-8- hydroxynaphthalene-3.6-disulphonic acid, 47.3 parts of 1-amino-8-tosyloxynaphthalene-3.6-disulphonic acid are used and, on completion of the coupling, the tosyloxy group is saponified to the hydroxyl group as described in detail in Example 1.

Example 3 47.3 parts of lamino-8-tosyloxynaphthalene-3.6-disulphonic acid are diazotised in the manner described in Example 1. The diazo compound is poured at 28-30- into a solution obtained by dissolving 28.7 parts of 3-methyl-l-dibenzylaminobenzene in 250 parts of hot ethanol. The mixture is then made weakly acid to Congo red by the addition of 57 parts by volume of sodium acetate solution and the whole is stirred at 28-30 until the diazo compound has disappeared, which is the case in a few hours. After distilling off the ethyl alcohol, the dyestuflf solution is neutralised with sodium carbonate and so much caustic soda is added that a 4% caustic soda lye is produced. After stirring for 1 hour at -85 the saponification of the tosyloxy group to the hydroxyl group is complete. The whole is neutralised with hydrochloric acid, the dyestuff is salted out, cooled, and the dyestufi which has precipitated in the form of a red crystal PQWder is filtered 01? and dried.

The dyestufi is a red powder which dissolves in water with a red c l ur. W ol s dy d from a n a t w ak y acid bath in very ciear, level red shades. The dyeings have excellent wet fastness properties and very good fastness to light.

Example 4 141.9 parts of l-amino-8-tosyloxynaphthalene-3.fi-disulphonic acid are diazotised as described; the diazo compound is poured at 30-32 into a solution of 113.7 parts of 2-(2'-methylphen0xy)-l-dibenzylaminobenzene in 1450 parts of ethanol. After stirring for an hour, care is taken to see that the reaction remains slightly acid to (pongo red by the dropwise addition of 40% sodium acetate solution. The whole is stirred at 30 for a further 8-10 hours until the diazo compound has disappeared. The mixture is heated and the ethanol is distilled off. The tosyloxy group is saponified to the hydroxyl group after neutralising with sodium carbonate by the addition of as much caustic soda as will produce a 4% caustic soda lye. The saponification is complete after stirring for 1 hour at 8085. The hot dyestuff solution is neutralised by the dropwise addition of hydrochloric acid, the dyestuff is salted out, filtered ofl'f after cooling and dried. It is a light red powder which dyes wool from a primary amino compounds by heating with an excess of benzyl chloride in the presence. of iodine as catalyst.

Example 5 parts of previously wetted W091 yarn are entered at 40 into a bath containing 4000- parts of water, 2 parts of the monoago dyestufi obtained according to Example 4, 10 parts i Glaubrs salt'a'nd 2 parts of acetic acid. The bath is brought to the boil within half an hour, 1 part of formic acid is addedand the bath is boiled for a further half hour. The yarn is :then'rinsed and dried. A very even yellowish-red clear wool dyeing is obtained which has very good wet and light fastnes s properties. l

The dyestuffs given in the following table are obtained by the methods described in Examples 1 to 4.

Shade of the d'y'estufi (it Diazo component Coupling component necessary saponifi'ed) on wool l-amino-8-tosyloxy-naphtha- 2.5 dimethyl l dibenz yllight red.

1ene-3.6-disu1phon.ic acid. aminobenzene. l-amino-S-hydroxy-napht-ha- 3-methoxy-1-dibenzylamiblue-red.

lane-3.6-disu1phonic acid. nobenaene. 1-amino-8-tosyloxy-g1aphtha- 2.5 dimet-hyl 1 di- (4 light red.

lene-Sfi-disulphonic acid. methoxybenzyl) aminos aen Do 2.5 dimethyl l d1 (4, Do.

' methylbenzyl) -aminobenzene.

What I claim is:

1. A monoaz'o dyestuff which contains only two sulphonic acid groups and which corresponds to the general formulaf i CHa-B r o s wherein Y1 and Y represent a member of the class con s ine o H and CH nd Z; and Z2 pre en a m e oi t ass c sists f and .61

3. A monoazo dyestuff corresponding to the formula: 

2. A MONOAZO DYESTUFF CORRESPONDING TO THE GENERAL FORMULA 